The invention provides an endurance test failure judgment method for an automobile transmission system. The endurance test failure judgment method includes the steps that i different working condition points t are set according to different rotating speeds n and different torques M, testing is carried out on a traditional system test piece at each working condition point t, the transmission efficiency at each working condition point t is obtained, then the i working condition points t are repeatedly tested, the transmission efficiency is calculated, an efficiency matrix is formed, and data filtering is carried out on the efficiency matrix; the mean values (please see the specification) and the variances sigma of the transmission efficiency of the working condition points t in the efficiency matrix are calculated, and a mean value change curve and a variance change curve are drawn; a mean value threshold value and a variance threshold value are set, when the mean values (please see the specification) are lower than the set mean value threshold value or the variances sigma are larger than the set variance threshold value, an alarm signal is emitted out, a device is notified to take stopping measures, and it is judged that the test piece fails. By means of the endurance test failure judgment method, interference can be effectively reduced, the foreboding generated before the transmission system fails can be effectively found, and early diagnosis can be achieved.